916 THE VOYAGE OF H.M.S. CHALLENGEK. 



in February 1875; it is 11 mm. long, and corresponds so closely with Amphion 

 reynaudii as shown on PL CXLVII. fig. 1, with the exception that it has only five 

 pairs of legs, that I thought it unnecessary to figure it beyond showing the frontal 

 margin of the carapace with the cephalic appendages (PL CXLVI. fig. 6), which viewed 

 from the dorsal surface are more distinctly shown than in any of the previous specimens. 



A specimen in this collection, which is given on PL CXLVII. fig. 2, corresponds 

 so closely with Amphion reynaudii of Milne-Edwards, that I have so named it ; I have 

 figured it with the greatest care, but the internal viscera are not in a well-preserved state, 

 the structure having been injured probably by being mounted in Canada balsam. The 

 cephalic and oral appendages are visible, as well as the hepatic organs and two pairs of 

 branchiae in an immature condition, corresponding with the pleura above the second pair 

 of gnathopoda and first pair of pereiopoda. This form is so little advanced towards 

 maturity that with the exception of the sixth pair of pleopoda, which forms part of the 

 rhipidura, no appendage of the pleon has advanced beyond the most incipient stage of 

 budding. 



The first somite of the pleon showing no trace of an appendage appears to me 

 evidence of its being a female, an idea that is supported by the presence of nucleated 

 hexagonal cells, a mass of which in a broken condition is retained on one side of the 

 median line, between the first and second pairs of pereiopoda ; this specimen is only 15 

 mm. long, whereas the two others show evidences of the male character, and these are 

 25 mm. Ions;. 



Two others w T ith six pairs of legs were taken in the Atlantic on the homeward voyage ; 

 one in March, the other in May, 1876. Of them I have taken the latter as the type of a 

 new species, the chief characteristics of which are a tooth on the dorsal surface of 

 the carapace and the form of the frontal margin of the carapace, which is without a tooth 

 in the median line, and has an excavation corresponding with the orbit, and in this 

 specimen the first pair of pleopoda is developed into a cylindrical uniarticulate rod, a 

 feature that I believe to be characteristic of the male animal rather than a specific character, 

 for with a slightly different formation it exists in a specimen found in the West Pacific 

 Ocean, and which in several respects corresponds with this species from the Atlantic, 

 among which I think may be seen a prominence like a tooth rubbed down, on the dorsal 

 surface of the carapace between the gastric region and the frontal margin. 



Among those taken in the West Pacific Ocean, north of New Guinea, there was a 

 specimen that I have represented in fig. 2 on PL CXLVII. Willemoes Suhm has 

 figured this same specimen I believe in fig. 76. This animal is well advanced 

 towards maturity and is fully described at page 910. In Suhm's drawing, the 



